Auxiliary Battery Problems; Sometimes Dead sometimes auto restart

Hi all!

Hoping to get some advice on whats going on with my battery/start up.

In May of 2016 I replaced my failing auxilary battery with an "Optima 8171-767 YellowTop Deep Cycle & Starting AGM Battery" About 8-10 months ago it started exhibting some strange behavior. Occasionally warning lights would come on (red triangle, check engine, and( (!)) ) sometimes they'd stay on, sometimes not.

Occasionally (once every few weeks) upon turning off the car it would immediately turn right back on with a bevy of warning lights and fans running.

One day I walked out (after having driven in the night before) and found that the car was totally dead, would not start at all, no power. Came back a few hours later and it started up fine no problem. It has only done with twice, once a few months ago and just now before I started writing this post (not sure if it will turn on when I get home from work).

A few days ago I checked the load on the battery using the maintenance menu. I checked it a few different ways, though I think I accidently had the air on during all tests.

with no brake, and the power button pressed only once: battery showed 12.2 v
pressing the power button a second time dropped to: 11.6v
turning on headlights dropped it to: 11.4v
turning the car on brought it up to: 14v


The car has about 110,000 miles on it. I bought it from my mom at around 80,000 miles, who bought it new in 2005. Recently (about 5 months ago) I replaced the inverter coolant pump (myself) and that seems to have worked fine. Headlights are a little dim, but may also be from how cloudy they are.


Any ideas or should I just order a new battery? If so any recommendations? I can't remember why I bought this one specifically.

 

Got home from work, still wouldn't start up. I unplugged the two cables that plug into the aux battery and plugged them back in firmly and the car started up. I'm not sure I understand at all how these plug in cables could be responsible for all the intermittent problems I've been having, and I assume if I check the load on the battery it will still be "bad."

No, the ground seemed to be quite firm at both ends. The positive connection on the battery is not as tight, but certainly not loose.

For what its worth it is quite hot where I live- so hot in fact that parts of the car have just been falling off. The plastic bolts in my driver side rear view mirror crumbled last year, the part where you grab on to unlock the back hatch came off and is now only attached by the electric cord and two clip screws, and the middle console screws broke as well. Unfortunately I bought the battery (new) on eBay over a year and a half ago, so I have a feeling they won't be giving me a refund, partial or otherwise.

But that leads me to my next question. Any recommendations on which battery to buy? I'm hoping this really is just an aux battery problem..but it concerns me that the battery went bad this quickly, as I know I checked the volts when I first installed it.

 

Does buying an oem battery from the dealer have a particularly longer warranty? I have had repeated bad experiences with the Toyota dealership here (they wanted to charge me $600 to install new wheel-well covers after failing to tell me that the bumper guard was dragging on the ground the last time I'd been in. Then wanted an equally insane amount to replace the inverter coolant pump.) and would prefer to avoid giving them any business. Though I guess if I was just buying the battery from them, they can't try to fork me too badly...

I probably drive it about 5-10k a year. It is my daily driver and I'd say I do drive most days (just not all that far usually).

 

Thanks, I'll call around.
I guess I'm a little confused on the not driving the car enough part. If I drive my car during the day I will probably be in it for 30 minutes to an hour and a half total. However because of the size of my city most of these trips are probably limited to 10-15 minutes a piece. Though I also occasionally take the car on trips to the coast, have taken it on much longer multi-day trips, etc. I guess I just don't know much about car batteries though!

The battery holds at 11.4. I will look into getting a trickle charger. Just to be clear the idea is that because I don't drive the car enough (or for long enough periods of time) I need something to occasionally bring the battery back up to full charge?

And I agree, the battery doesn't seem to be "low" enough to be causing all of these problems. Certainly not the completely dead, and auto-restart issues.

I sort of mentioned which lights were on in the first post, but the problem is these warning lights aren't consistent at all. One day the triangle, check engine and (!) were on, and then later turned themselves off. About a month or two ago the large Triangle was on for multiple days along with the check engine. And then they both turned off on their own. After the car wouldn't turn on at all the first time I took it in to have the codes read (after it mysteriously just started back up later) and the only code that came up was P3191 (engine will not start). For the past few weeks no warning lights have come on during regular usage. When the car does the auto-turn back on when I park and turn it off (again this only happens maybe once every few weeks), I am usually too flustered to remember to write down which lights are on - or to even write down which mode it has turned back on to (if I am recalling correctly, I think it is in the second mode, as if i had turned the car on with no brake). It only happens once every several dozen turn offs, which is long enough that I am taken by surprise each time.

So i understand that the errors may still be there, but because the 12v is messing up it may be continously clearing the codes?
The Hybrid battery was replaced about 2 years ago by the Toyota dealership. The car isn't showing any "driving" problems so a transaxle failure seems a bit..unlikely? Not sure what signs I'd see if the A/C Compressor was failing, but I can say that the A/C is pretty much always on (we have routinely had 100-110 weather for weeks on end this summer).

If I drive it around for the next few days is it worth trying to read the codes again even if no warning lights show up?

 

Also for what its worth... after two errands today, came out and turned it on and it didnt quite start up. tried again and and it started up fine. Interestingly the clock didn't reset..but it seems to have sometime after I reset it this morning. The sensor for the gas tank and reset, etc.


Should I be checking for a short (and any recommendations on how I would go about doing so?) or be checking the fuses?